Add support for passing common help switches like -? or --help to tests.sh to get a usage string
Add support for passing common help switches like -? or --help to tests.sh to get a usage string

dotnet/roslyn,swaroop-sridhar/roslyn,jcouv/roslyn,tmat/roslyn,eriawan/roslyn,jmarolf/roslyn,aelij/roslyn,shyamnamboodiripad/roslyn,genlu/roslyn,ErikSchierboom/roslyn,mgoertz-msft/roslyn,stephentoub/roslyn,diryboy/roslyn,diryboy/roslyn,jmarolf/roslyn,sharwell/roslyn,davkean/roslyn,mavasani/roslyn,tannergooding/roslyn,shyamnamboodiripad/roslyn,panopticoncentral/roslyn,AmadeusW/roslyn,abock/roslyn,panopticoncentral/roslyn,abock/roslyn,reaction1989/roslyn,bartdesmet/roslyn,jcouv/roslyn,DustinCampbell/roslyn,wvdd007/roslyn,sharwell/roslyn,eriawan/roslyn,mavasani/roslyn,gafter/roslyn,xasx/roslyn,stephentoub/roslyn,agocke/roslyn,brettfo/roslyn,agocke/roslyn,physhi/roslyn,aelij/roslyn,mavasani/roslyn,weltkante/roslyn,davkean/roslyn,mgoertz-msft/roslyn,jmarolf/roslyn,AmadeusW/roslyn,VSadov/roslyn,AlekseyTs/roslyn,heejaechang/roslyn,genlu/roslyn,MichalStrehovsky/roslyn,dotnet/roslyn,diryboy/roslyn,reaction1989/roslyn,dotnet/roslyn,CyrusNajmabadi/roslyn,nguerrera/roslyn,MichalStrehovsky/roslyn,stephentoub/roslyn,abock/roslyn,tannergooding/roslyn,xasx/roslyn,VSadov/roslyn,jasonmalinowski/roslyn,bartdesmet/roslyn,mgoertz-msft/roslyn,gafter/roslyn,CyrusNajmabadi/roslyn,tmat/roslyn,physhi/roslyn,wvdd007/roslyn,AlekseyTs/roslyn,DustinCampbell/roslyn,KirillOsenkov/roslyn,jasonmalinowski/roslyn,sharwell/roslyn,heejaechang/roslyn,davkean/roslyn,KevinRansom/roslyn,tannergooding/roslyn,shyamnamboodiripad/roslyn,physhi/roslyn,AmadeusW/roslyn,reaction1989/roslyn,DustinCampbell/roslyn,panopticoncentral/roslyn,MichalStrehovsky/roslyn,AlekseyTs/roslyn,eriawan/roslyn,KevinRansom/roslyn,agocke/roslyn,swaroop-sridhar/roslyn,ErikSchierboom/roslyn,gafter/roslyn,weltkante/roslyn,nguerrera/roslyn,jasonmalinowski/roslyn,wvdd007/roslyn,nguerrera/roslyn,heejaechang/roslyn,brettfo/roslyn,genlu/roslyn,brettfo/roslyn,ErikSchierboom/roslyn,VSadov/roslyn,KirillOsenkov/roslyn,tmat/roslyn,bartdesmet/roslyn,KirillOsenkov/roslyn,jcouv/roslyn,xasx/roslyn,aelij/roslyn,swaroop-sridhar/roslyn,CyrusNajmabadi/roslyn,weltkante/roslyn,KevinRansom/roslyn